1. Field of the Invention
The present invention relates to supercapacitors and more particularly to microelectronic supercapacitors formed from micro electromechanical systems (MEMS) techniques formed with volumes xe2x89xa61 mm3.
2. Description of the Prior Art
Supercapacitors are generally known in the art. Examples of such supercapacitors are disclosed in U.S. Pat. Nos. 5,151,848 and 5,426,561, hereby incorporated by reference. In general, such supercapacitors relate to high surface area capacitors, such as double layer capacitors, which can provide up to 2000 times the volumetric capacitance of conventional electrolytic capacitors.
Various applications exist which require power supplies including capacitors that are limited in size to a few cubic millimeters of volume. Examples of such applications include high-speed electronic applications that require on-chip/on-board power supplies to prevent local current starvation. Other applications include microsensors and military applications, such as precision munition systems.
Supercapacitors are known to be used with power supplies to speed up the delivery of the electric energy stored in a battery to a load. More particularly, power supplies are formed from energy storage devices, such as a battery. Such energy storage devices are normally characterized by energy density (i.e. energy stored per unit of volume or mass) and power (how fast the energy can be delivered). In order to increase the power or rate at which the energy within the battery can be delivered to a load, supercapacitors are known to be coupled to the battery. Unfortunately, known supercapacitors are component size (i.e. much larger than a few millimeters of volume) and are thus not suitable for use in the various applications discussed above. Thus, there is a need for supercapacitor having a total volume of less than a few cubic millimeters.
The present invention relates to a microelectronic supercapacitor that is amenable to being fabricated using micro electromechanical systems (MEMS) techniques. By utilizing MEMS techniques, the supercapacitor in accordance with the present invention can be formed with volumes xe2x89xa6mm3. As such, such microelectronic supercapacitors are suitable for use in applications as discussed in which only a few cubic millimeters are available for both a supercapacitor and an energy storage device, such as a battery.